Catalase is a common enzyme found in almost all living organisms that use oxygen. Catalyzes the decomposition of hydrogen peroxide into water and oxygen. Catalase is a critical enzyme that protects cells from oxidative damage caused by reactive oxygen species (ROS).
Catalase measurement in the context of Oxidative Stress tests can help identify the underlying causes of many chronic diseases and clinical disorders so that appropriate individualized therapeutic interventions can be designed.
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Catalase is one of the antioxidant enzymes, such as superoxide dismutase (SOD) and glutathione superoxidase, and is produced generally in all cells of the body. Catalase can also catalyze oxidation through hydrogen peroxide, potentially harmful toxins to the body, including alcohol, phenol, and formaldehyde.
All aerobic organisms need oxygen to live, but when cells use oxygen, free radicals are produced that damage cell membranes, proteins, and DNA. Free radicals are chemically unstable atoms or molecules that create other unstable atoms and molecules in the body. This process causes extensive damage to cells and tissues and can lead to damage to the immune system, infections and inflammation, cardiovascular diseases, and neurodegenerative diseases, among others. Free radicals are also considered a key element in the aging process.
Catalase works closely with superoxide dismutase to prevent free radical damage to the body. Superoxide dismutase converts the dangerous peroxide radical to hydrogen superoxide, which then catalase catalyzes the conversion to harmless water and oxygen. Catalase is one of the most effective enzymes found in cells. Each catalase molecule can convert millions of molecules of hydrogen superoxide to water and oxygen every second.
Hydrogen peroxide is a natural but destructive byproduct of the metabolism of all oxygen-dependent organisms. It is produced in the human body when fatty acids are converted into energy and when white blood cells attack and kill microbes. Catalase, found in the cell's peroxisomes, prevents this usually-produced hydrogen peroxide from damaging the cell during these processes. It also helps prevent the conversion of hydrogen peroxide into hydroxyl radicals, potentially dangerous molecules that can react with DNA and cause mutations.
It is believed that one of the leading causes of cell aging is DNA damage caused by free radicals and oxidizing agents such as hydrogen peroxide. Increasing levels of the body's natural defense antioxidant systems—enzymatic (catalase, peroxide dismutase, etc.) and non-enzymatic (vitamins, glutathione, etc.) - can improve health. It is possible that aging is ultimately the result of exposure to free radicals and not the passage of time.
Low levels of catalase may play a role in graying hair in humans. Hydrogen peroxide, usually produced by the body, is broken down by catalase. Hydrogen peroxide cannot be broken down effectively if catalase levels are reduced. Hydrogen peroxide interferes with melanin production, the pigment that gives hair its color. Mice that are genetically engineered to lack catalase are initially phenotypically normal. However, catalase deficiency in experimental animals may increase the likelihood of developing obesity, fatty liver disease, and type 2 diabetes.
Structurally, catalase is a tetramer of four polypeptide chains. It contains four heme groups containing iron, which allow the enzyme to react with hydrogen peroxide. Any metal ion (such as copper cations) can act as a non-competitive catalase inhibitor. The optimum pH for human catalase is about 7.
